
In addition to the above enforced restrictions, the parameters are also subject to the constraints discussed in section REF ,
including vacuum stability (REF ) and the conditions to ensure the existence of
stationary points at the symmetric phase \((0,~w_0)\)  and the broken phase \((v,~w)\) . Further constraints come from the requirement of perturbative unitarity [1]}, [2]}
\(\lambda _{h}<4 \pi ,~ \lambda _{s}<4 \pi ,~|\lambda _{m} |<8 \pi ,~3 \lambda _{h}+2 \lambda _{s}+\sqrt{\left(3 \lambda _{h}-2 \lambda _{s}\right)^{2}+2 \lambda _{m}^{2}}<8 \pi .\) 
